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Science: Why Lefties Make Better Baseball Players

Watching the Twins' Justin Morneau lead off the winning rally in the 15th inning of Tuesday night's All-Star game with a single to shallow center, there was no reason to be surprised that he throws righty but bats lefty. Although only one in 10 civilians are left-handed, one quarter of Major League Baseball players are southpaws. That's no accident, says Washington University aerospace engineer David Peters, who has used math and physics skills to confirm that lefties have a considerable advantage on the diamond. Of the 40 players in Tuesday's All-Star game, 18 are either left-handed batters or switch-hitters. And it's not just the MLB where lefties excel, says Peters. Among the thousands of young players populating the nation's baseball and softball fields for summer tournaments, chances are the left-handers are getting on base more frequently and pitching better than their righty counterparts. NEWSWEEK's Andrew Bast spoke with Peters about the mechanics of national pastime. Excerpts:

NEWSWEEK: You argue that left-handers have a distinct advantage in baseball. Why? David Peters: Twenty-five percent of players are left-handed, where in real life only 10 percent [of people] are left-handed, so that's proof that they are two-and-a-half-times better. There are several reasons why. One reason is that the left-handed batter is closer to first base, so he's got a couple steps advantage trying to beat out a grounder. Over the course of a year, he's going to beat out a few more. Also, as he swings, his momentum is turning him toward first base. But that is not the biggest advantage. The biggest has to do with the angle of the ball. Three quarters of pitchers are right-handed. A right-handed batter has to look over his left shoulder and the ball is coming at quite an angle. The offset of your eyes gives you depth perception. So when you're looking over your shoulder, you have lost the distance between your two eyes quite a bit, so you have lost that 10th of a second to see the ball. That's why batters switch hit.

Is the inverse also true? A left-handed hitter facing a left-handed batter means double trouble. First, it's coming over his shoulder, but second, he hasn't seen that many left-handed pitchers, because he's mostly learned from right-handed pitchers.

And the stadiums, too?Most ballparks were built thinking of right-handed batters. The left field was usually further away than right because of the power of right-handed batters. So when a lefty comes to the plate, he's got that short right field. I used to watch Stan Musial when I was a kid in the old Sportsman's Park where they had a very short left-field pavilion. Or [the] Polo Grounds in New York was the same. All of those old parks definitely had a shorter right-field fence. And, of course, the House that Ruth Built, Yankee Stadium, is a prime example.

Do coaches make calculated judgments accordingly?Yes, they have all kinds of statistics how every batter hits against both righty and lefties. For instance, the Cardinals have Chris Duncan who probably doesn't start if there is a left-handed pitcher. That is why switch-hitters change when they do. Now some batters do better with their stance, but most lefties have a big advantage.

A friend of mine says that his mother lied to him all his life, telling him he was really a lefty, only to recently discover that he's right-handed. If we want our kids to make the big leagues, maybe we ought to do the same?No, teach them to switch hit. That is what Mickey Mantle's dad did. From day one when Mantle was 5 years old, he learned from both sides. Pete Rose was a similar kind of story. That gives you the advantage. I was actually left-handed, and my parents and schoolteachers actually made me switch. They weren't thinking about baseball as much as they were thinking about normalcy. I stutter to this day because of it. The desks at school, scissors, the Palmer Method of penmanship, none of them worked for a lefty. Now, throwing in baseball is not as critical, though there has hardly ever been a left-handed catcher, because most batters are right-handed so if you want to throw out someone stealing second, the batter is in the way. Babe Ruth wanted to be a catcher, but there were no mitts for lefties. So they made him a pitcher instead.

Would all the same lefty rules apply to softball, also? In fast-pitch, it's the very same thing. In fact, it's a bit shorter to first base, so that extra head start is even more important. Also, the pitcher is so much closer in softball, the reaction time is cut down even further.

This year's Wimbledon winner is Rafael Nadal—a right-hander who plays tennis left-handed. Does the left-hand advantage carry into other sports?There is always the advantage that the other player hasn't seen as many lefties. It's the same in boxing. A left-handed boxer circles a different way. Even in bowling, left-handers have an advantage because the lanes wear from so many right-handed bowlers and the lefty doesn't get caught in that worn groove. One game that doesn't work for left-handers though is jai alai.

You're an aerospace engineer. Should major-league front offices start talking more to scientists?There's a lot of things they should talk about. Now we have trouble with the maple bats, and there's a question whether we ought to use aluminum. Scientists could help a lot there. We had the controversy with the ball, how it was getting more lively with all the home runs. Already a lot of teams have mathematicians and computers in their dugouts figuring probabilities. So there is a lot of place for science in the game of baseball. Ted Williams was really the first to think of hitting as a science. He discovered it was bat speed, not bat weight that was so important. After him, people went to lighter bats. Ruth used some huge 36-ounce bat, but Williams discovered, no, it's actually the speed.

Though you can probably explain why a curveball actually works. It's Bernoulli's principle. Take an overhead curve heading for home plate, for example. It's got topspin. From the top of the ball, the stitching and the leather tends to slow down the air. Whereas the bottom of the ball is spinning back toward the pitcher and is actually pulling the air and speeding it up. It's how an airplane wing works. You get more force on the top of the ball than on the bottom and that pushes it down.

Today you have curveballs, sliders and change-ups. Are there any pitches still to be developed?I think there are. The Japanese have been working on different kinds of spins that nobody has ever done before. There's not a ball now that really spins with its axis from the pitcher to the catcher on a horizontal plane. People have been trying to see what that would do. Of course, the knuckleball doesn't spin at all, so the air can't decide which side it wants to go on and you don't know which way it is going to go. You know, back when the curveball was first invented, the president of Harvard declared that his baseball team would not throw it because it was unsportsmanlike.

One of my colleagues broke his hand this summer sliding into first. Do you have a theory that might make him feel better?The only time you should slide into first base is if the first baseman is getting pulled off the bag by a wide throw so he has to tag you. In that case it might get you under the tag. But otherwise you're faster overrunning it. Now there are people who swear by diving. Their argument is that when you dive and your feet leave the ground you keep the same speed but get your hands out in front of you. Only, there's air friction. Though, I think if diving was in fact better, people would probably do it more.

The Cardinals are your team. How do they look for the second half of the season?Everybody else is making moves—Milwaukee, Chicago. And we're just sitting here. It's going to be tough to catch the Cubs, but we might get a wildcard berth. You never know. We've got a bunch of young guys. We have almost the best starting pitching, but our bullpen has been horrible.

Maybe you need some left-handed relievers.That's exactly what we need.